Coloradia pandora (Blake) is a phytophagous insect that defoliates Pinus ponderosa (Dougl. ex Laws.) in south-central Oregon. Little is known about the extent of damage this insect inflicts upon its host trees during an outbreak. In this paper, we present stem analyses on four dominant Pinus ponderosa trees that enable us to determine the amount of volume lost during each Coloradia pandora outbreak on this site for the past 450 years. We found that on average an outbreak inhibits radial growth so that an individual tree produces 0.057 m³ less wood volume than the potential growth for the duration of an individual outbreak. A total of 0.549 m³ of growth per tree was inhibited by 10 outbreaks during the lifetime of the trees, which, in this stand, equates to 9.912 m³/ha (1,700 board feet/acre) of wood suppressed over the last 450 years throughout the stand. Our results do not support previous findings of a lag in suppression onset between the canopy of the tree versus the base. Crossdating of stem analysis samples is paramount to definitively examine the potential for a lagged response throughout the

White-tailed deer are ecosystem engineers that dramatically alter forest understory vegetation. Consequently, deer can impact many species in a forest through both direct and indirect effects. One species that deer may indirectly affect is the gypsy moth, whose pupae are preyed upon by the white-footed mouse. Through alterations to understory habitat of mice, deer may reduce mouse predation on gypsy moth pupae. In this study, I tested for indirect effects of deer on the gypsy moth by comparing mouse abundance, vegetation properties, and predation on pupae inside, and outside, of long-term deer exclosures. Overall, I did not find evidence for indirect effects of deer on the gypsy moth. There was little effect of the exclosures on mouse abundance, predation rates, and habitat measures. High mouse abundances, which likely resulted from a large acorn mast the previous year, may be obscuring indirect effects that would be detected at lower mouse abundances.

Understanding movement capabilities of individuals within a landscape is essential to identifying the effects of habitat boundaries on species abundances, ranges, and spread rates. Movement barriers due to habitat fragmentation may reduce mate-finding ability in some species, particularly in heterogeneous landscapes containing low-density populations. This study focuses on the effects of habitat type and edge on mate-finding in an invasive defoliator, the European gypsy moth. Adult European gypsy moth males locate mates by following pheromones released by flightless females. Reduced mate-finding was expected in fields and near forest edges based on geographic variation in invasion rates and pheromone plume dynamics. A male release-recapture experiment using female-baited traps in fields, at forest edges, and in the forest interior showed that mate-finding was highest at forest edges, reduced in fields, and lowest within the forest interior. This suggests that forest edges and moderate habitat fragmentation enhance mate-finding in the gypsy moth.

A mariposa Plutella xylostella (L., 1758) (Lepidoptera, Plutellidae), conhecida popularmente como traça das crucíferas, é uma importante praga da cultura das brássicas no Brasil e em diversos países. Seu controle normalmente é realizado com aplicações freqüentes de inseticidas convencionais, porém esse controle tem se mostrado ineficiente, além dos problemas ambientais, econômicos e de resistência de insetos que pode causar. A quimioesterilização apresenta-se como uma alternativa para o manejo desta praga, utilizando inseticidas modernos, mais seletivos aos inimigos naturais e de menor impacto ambiental. O objetivo deste trabalho foi estudar o emprego de alguns inseticidas com propriedades esterilizantes sobre a fase adulta de Plutella xylostella determinando as dosagens adequadas que atuaram sobre sua reprodução. Os produtos foram fornecidos às mariposas em forma de iscas que consistiram em: solução do produto + melaço 10%. Os inseticidas utilizados e suas respectivas dosagens foram abamectina (0,0025 g i.a./L calda), diflubenzurom (0,005 g i.a./L calda), lufenurom (0,005 g i.a./L calda) e piriproxifem (0,01 g i.a./L calda), além da testemunha. Apenas o tratamento com abamectina afetou a fecundidade de Plutella xylostella, apresentando 10,23 ± 4,41 ovos em média, enquanto na testemunha obteve-se 64,54 ± 15,11 ovos, porém a fertilidade foi afetada por todos os produtos. A viabilidade média dos ovos dos tratamentos com abamectina, diflubenzurom, lufenurom e piriproxifem foi, respectivamente 3,35%; 46,69%; 9,31% e 12,47%; todos diferiram estatisticamente da testemunha que apresentou viabilidade de 83,89%. A longevidade dos insetos tratados com os produtos não diferiu dos não tratados, com exceção dos indivíduos tratados com abamectina que apresentaram uma redução no tempo de vida. Quando os produtos testados foram oferecidos isoladamente para machos e fêmeas, a ação esterilizante apenas pode ser observada em fêmeas desta espécie, os machos não apresentaram nenhuma diferença com relação à testemunha quando alimentados com as iscas esterilizantes. / Plutella xylostella (L., 1758) (Lepidoptera, Plutellidae), commonly known as diamondback moth, is an important pest of Brassicaceae in Brazil and several other countries. Its control is usually done with frequent applications of conventional insecticides. However, this approach is sometimes ineffective, besides some drawbacks such as environmental contamination, the high cost of application and the development of insecticides resistance. Chemosterilization using modern insecticides presents an alternative for this pest management. The aim of this study was to evaluate a range of insecticides with sterilizing properties on the adult reproduction of Plutella xylostella. Pesticides were provided to moths in baits, diluted in 10% molasses water solution. The insecticides used and respective doses were: abamectin (0.0025 g a.i./L), diflubenzuron (0.005 g a.i./L), lufenuron (0.005 g a.i./L) and pyriproxyfen (0.01 g a.i./L). A 10% molasses solution was used as a control treatment. Only abamectin affected the fecundity of Plutella xylostella, with a reduction from 64.54 ± 15.11 eggs/moth obtained in the control treatment to 10.23 ± 4.41 eggs/moth, when adults were fed this pesticide. However, fertility was affected by all pesticides. Egg viability when adults were feed abamectin (3.35%), diflubenzuron (46.69%), lufenuron (9.31%) and pyriproxyfen (12.47%) were reduced when compared to the control (83.89%). Only adults that were abamectin fed had their longevity reduced as compared to all other treatments. When the tested pesticides were offered isolated to males or females, their sterilizing activity was observed only when females had access to treated baits.

A traça das crucíferas, Plutella xylostella (L.) (Lepidoptera: Plutellidae), é uma das pragas mais importantes de Brassicaceae no Brasil e no mundo, causando sérios danos em repolho, couve-flor e couve comum, entre outras. O objetivo desta pesquisa foi estudar os parâmetros populacionais e a resposta comportamental de P. xylostella criada por dezoito gerações, utilizando três variedades: Brassica oleracea var. acephala couve manteiga hibrida HS-20, B. oleracea var. italica couve brócolis Piracicaba e B. oleracea var. capitata repolho Bob Cat. Para condução dos experimentos foram separados três lotes de pupas de P. xylostella da criação mantida no laboratório, no qual foram utilizadas apenas folhas de couve para sua manutenção. Cada lote foi mantido em substrato diferente, ou seja, a criação inicial foi dividia em três populações tendo como variável o substrato alimentar e de oviposição utilizado na criação (couve, brócolis ou repolho). Com os dados biológicos de P. xylostella foram estimados os parâmetros populacionais de tabela de vida de fertilidade a cada três gerações, comparando-se as cultivares testadas em relação ao desenvolvimento, sobrevivência e reprodução da praga. Além disso, lotes de insetos oriundos de cada substrato de criação foram separados a cada três gerações para realização de testes de dupla e múltipla chance de escolha (preferência para alimentação e oviposição). Os parâmetros populacionais de P. xylostella indicam que as brassicáceas testadas permitem o crescimento populacional do inseto nos respectivos hospedeiros. O comportamento de seleção hospedeira na fase pré-imaginal e imaginal de P. xylostella não é afetado pela experiência alimentar e de oviposição nos substratos testados até a geração F18. / The diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), is one of the most important pests of Brassicaceae in Brazil and worldwide, causing serious damage to cabbage, cauliflower and kale common, among others. The aim of this research was to study the population parameters and the behavioral response of P. xylostella reared for eighteen generations, using three varieties: Brassica oleracea var. acephala - cabbage hybridizes HS-20, B. oleracea var. italica - Piracicaba broccoli and B. oleracea var. capitata - cabbage Bob Cat. To conduct the experiments were separate three batches of DBM from pupae held in the laboratory setting, in which only kale leaves were used for maintenance. Each batch was kept at different substrate, namely the initial rearing was divided into three populations having as variable the feeding and oviposition substrate used in rearing (kale, broccoli, and cabbage). With biological data of P. xylostella were estimated the population parameters of fertility life table every three generations, comparing the tested cultivars in relation to the development, survival and reproduction of the pest. Moreover, lots of insects derived from each rearing substrate were separated every three generations for performing dual choice and multiple-choice tests (preference for feeding and oviposition). The population parameters of P. xylostella indicate that brassicas tested allow the insect population growth in their hosts. The host selection behavior in pre-imaginal and imaginal stage of P. xylostella is not affected by food and oviposition experience on substrates up to F18 generation.

Digitized by Kansas Correctional Industries

Includes bibliographical references (leaves 204-230). Investigates the behaviour and ecology of the two major larval parasitoids of the diamondback moth, Plutella xylostella; Cotesia plutellae and Diadegma semiclausum.

Includes bibliographical references (leaves 204-230). / xvi, 230 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Investigates the behaviour and ecology of the two major larval parasitoids of the diamondback moth, Plutella xylostella; Cotesia plutellae and Diadegma semiclausum. / Thesis (Ph.D.)--University of Adelaide, Dept. of Applied and Molecular Ecology, 2001

The cinnabar moth, Tyria jacobaeae (L.) (Lepidoptera:Arctiidae), was released in 1959 to control the grassland weed tansy ragwort, Senecio jacobaea L. (Asteraceae), despite evidence that caterpillars of this species can feed on native plants within the genera Senecio and Packera. Previous studies confirmed the moth's ability to develop on the native Senecio triangularis Hook., although no systematic study has been conducted to determine the extent of non-target impact on all potential host species. To address the lack of systematic studies we conducted a regional survey to determine the consequences of exposure of non-target plants to cinnabar moth caterpillars. We also conducted a local field experiment to determine the influence of habitat on the patterns of association of the moth and non-target plants. In the regional survey, we mapped the potential distribution of the cinnabar moth in Oregon to determine the extent of exposure of native Senecio and Packera species, and systematically sampled exposed species to assess the frequency and severity of feeding on these plants. We found that nine of the 20 native non-target species in Oregon were exposed to the cinnabar moth, three of the 10 native Senecio and six of the 10 native Packera. Ten of the native species escaped exposure because they occur east of the Cascade Mountain Range where the cinnabar moth does not occur. We found feeding damage on three of the nine exposed species: Packera cymbalarioides, P. pseudaurea, and S. triangularis were attacked at one of three (33%), two of six (33%), and seven of 15 (47%) sites that supported populations of each species, respectively. Within sites, attack frequency of stems was 33% (of six total stems sampled) for P. cymbalarioides, and ranged from 53% to 56% (of 20 to 108 total stems sampled) for P. pseudaurea and 7% to 64.5% (of 32 to 458 total stems sampled) for S. triangularis. Conditional median damage per site (median of attacked stems only) was 10% in P. cymbalarioides, 5% to 17.5% in P. pseudaurea, and 5% to 37.5% in S. triangularis. The attack rate on non-target plants (7.1 to 64.5 percent of stems attacked at a singe site) was equal to or greater than on the target weed (8.3 to 50.0 percent of stems attacked at a single site). At three sites, caterpillars attacked non-target plants but the target weed was absent, and at one site, the target was present but caterpillars fed on non-target plants only. We conclude that attack frequency and severity on the three species is not high, but equaled or exceeded the level of attack on the target weed. We also conducted a mark-release-recapture experiment to relate habitat preference to patterns of non-target host use in the field. We compared adult moth dispersal patterns and larval development between a meadow habitat and a forest habitat. We found that long-term dispersal distance (spanning days) was similar in both habitats but we recaptured a higher percentage of moths from the meadow (47%) compared to the forest (10%). Short-term displacements, based on direct observations of flights immediately after release, differed between habitats: moths in the meadow flew short distances (8.5m ± 1.5, n=13) at or below the herbaceous canopy (0.8 m ± 0.2, n=13) while moths in the forest flew longer horizontal (22.8 m ± 2.8, n=15) and vertical distances (5.9 m ± 0.9, n=15). We recovered seven fifth instar larvae (of 278 eggs) from the meadow habitat but no larvae beyond the second instar (of 119 eggs) were recovered from the forest habitat. We conclude that the cinnabar moth is limited to meadow habitats because adult moths display movement patterns that remove them from forest habitats (possibly due to disorientation) and larvae are unable to survive on plants growing in the forest. Taken together, the regional survey and the local field-experiment indicate that the cinnabar moth uses only a small proportion of available non-target host plant species. Other species are likely unused because of geographic isolation from the moth, habitat selection by the moth, or phenological differences between the moth and non-target plants. / Graduation date: 2003

The biology and behavior of the codling moth, Cydia pomonella (L.), was studied to determine factors responsible for differences in susceptibility to moth damage among apple and pear cultivars. In release experiments, codling moth adults were intercepted in significantly greater numbers in host (apple, pear) than in non-host (maple) trees, suggesting a directed response rather than random movement to host trees. There was no correlation between adult preference for certain hosts and the susceptibility of the hosts to codling moth attack. Adults were guided by cues from the tree canopy, foliage and fruit. Cues from host fruit were less important at the beginning of the season. Similar adult behavior patterns were observed in different coding moth strains. However, moths reared on apples were guided more by olfactory cues from fruit than sterilized moths reared on artificial diet. The percentage of moths mating under caged conditions was higher in apple and pear than in maple trees. In host plants, stimuli from fruit were not essential for mating. The egg distribution in the field varied through the season depending on the host cultivar. However, mean distance of eggs to fruit, as well as larval travel speed, was not different among host cultivars. Selection of an oviposition site by the adult female was affected by several factors, including visual, chemical, and tactile stimuli of host fruit, as well as anatomical (pubescence) and chemical (oviposition stimulants) properties of leaves. There were no differences in natural mortality and developmental rates of the egg stage on host cultivars. However, there were significant differences in first instar larval mortality among hosts over most of the season. Mortality was much higher on 'Anjou' than on 'Bartlett' and 'Red Delicious', except at the end of the season. Differential first instar mortality was due to the different rate of success in entering the fruit. The ability to penetrate fruit was correlated with infestation levels observed in the field and related both to neonate behavior and anatomical characteristics of host fruits. Larval food source did not affect larval and pupal development rates, adult fecundity, or egg viability. / Graduation date: 2001